SYDNEY - THREE Australians convicted of heroin smuggling in Indonesia have had their death sentences reduced to life imprisonment, a report said on Thursday.

The Supreme Court in Jakarta has decided to spare the lives of three of the so-called 'Bali Nine' - Si Yi Chen, Matthew Norman and Tan Duc Thanh Nguyen, The Daily Telegraph reported.

Australian Foreign Minister Stephen Smith said the government was trying to confirm the reports.

'If the reports are accurate then of course it's very welcome,' he told Nine Network television.

The newspaper said court documents and an interview with one of the judges revealed the trio's previous good character, and that their youth had played a major role in the decision to grant them mercy.

The three had launched a final appeal claiming a court which had increased their sentence from 20 years to the death penalty had ruled in error.

Judge Hakim Nyak Pha said there had been 'intense discussion' about what penalty was appropriate, the paper reported.

'It's not their job. They are not masterminds and they are not earning their money from smuggling,' he said.

The three had expressed remorse and apologised to the court for their stupidity.

Chen, Norman and Nguyen were known as the Melasti Three because they were arrested at the Melasti hotel in Bali. None of the three had drugs on them at the time, but police found 350 grammes of heroin in a suitcase in their room.

Three members of the 'Bali Nine' remain on death row while three others are serving prison sentences ranging from 20 years to life for their roles in the plot.

All were convicted of trying to traffic heroin from the Indonesian resort island of Bali to Australia in 2005. -- AFP